下寺湾油田延长组长9致密砂岩储层特征及主控因素分析

Properties and the Main Controlling Factors of Tight Sandstone Reservoir of Chang 9 Member in Xiasiwan Oil Field

下寺湾油田延长组长9段致密砂岩储层特征研究程度低,致密油勘探未取得突破性进展。为了探明研究区延长组长9段致密油的勘探前景,从岩心样品分析入手,通过观察铸体薄片、扫描电镜,并进行压汞曲线分析、以及岩心样品物性分析测定等对下寺湾油田长9致密砂岩储层微观结构特征及主控因素进行了研究。结果表明长9段储层岩性以灰色岩屑长石砂岩为主,结构及成分成熟度均较低;填隙物以胶结物为主,胶结物以绿泥石、伊利石、铁方解石为主;孔隙类型以溶蚀粒间孔为主;孔喉大小分布不均,分选性较差,总体吼道半径较小;浊积主水道及绿泥石环边胶结相对优质储层发育起着主要控制作用。

No breakthrough has been made in tight oil exploration of Chang 9 member of the Yanchang Formation in Xiasiwan oil field, because of the low level of research on tight Sandstone properties. In order to evaluate tight oil exploration prospect of Chang 9 member of the Yanchang Formation,on the basis of a large number of core data, physical property analysis, casting thin sections and scanning electron microscopy(SEM), mercury injection and other methods, a detailed study is carried out in Chang9 reservoir, Which includes petrologic characteristics, pore structure characteristics, physical property characteristics and the main controlling factors of tight sandstone reservoir. The study shows that lithology of Chang 9 reservoir gives priority to grey arkose,structure and component maturity is low.Filling content is mainly of cement, it is mostly iron calcite, chlorite and illite. Poretypes are mainly feldspar intergranular dissolved pore. Pore size distributary is wide, sorting characteristics are poorer,pore throat radius is smaller. Turbidity main channel and chlorite cementation controlling the high quality reservoir development play an important role.